The present invention relates to a thermostatic switch that may be utilized in electrical appliances, copying machines, computers and many other electrically operated devices and machines. The present switch includes provision for reset mechanism for reestablishing electrical communication therein.
Reset devices for thermostatic switches have been utilized heretofore and have normally included a manually operable plunger that was engageable with an actuating member that was, in turn, engageable with a bimetallic disc. Thus, in the prior known devices resetting of the circuit in the switch was accomplished by depressing a reset element to move the actuating member directly into engagement with the bimetallic disc, wherein the bimetallic disc was urged to the switch-closed position.
Although the prior known thermostatic switches which included a manual reset control performed the function of resetting the movable contact member to the closed position thereof, it was not always desirable to return the movable contact member to the closed position and establish electrical communication through the switch, until the bimetallic disc in response to the changing environmental temperature had returned to the original or switch closed condition. Thus, often times the movable contact member in the prior known thermostatic switches was prematurely returned to the closed position thereof, and this in some instances resulted in malfunction of the device or other temperature-related hazard. In many such cases it is desired to open or close an electric circuit and retain it in such condition until after human intervention or investigation. It is then desired to return the circuit to its original condition, but only after the temperature has returned to a previous level.
In an apparent effort to avoid this problem, switches have been provided with sliding catch and release members. Such switches are generally larger than desired and may be unreliable in operation. Such a switch is shown in Cox U.S. Pat. No. 3,081,388.